Process cartridges which are detachably mounted in image-forming apparatus are well known in the art. Also, it is well known in the art to provide structure for holding a part of the casing of the process cartridge by a positioning member mounted in the main assembly of the image-forming apparatus. Such structure is disclosed in U.S. Pat. Nos. 4,591,258; 4,566,777; 4,575,221; and 4,588,280.
Typically, a small clearance is provided between the casing and the ends of the drum so that the photosensitive drum may rotate smoothly. Typically, the drum is provided with a helical gear at one end thereof for meshed relation with a second helical gear of the output shaft of the image-forming apparatus which imparts a longitudinal thrust force on the drum, which also imparts a longitudinal force and displacement of the casing while simultaneously rotating the drum. Such longitudinal force displaces the photosensitive drum and casing in the direction of the positioning member of the image-forming apparatus and thus creates excessive friction between the end of the rotating drum and casing once the casing has come to rest against the positioning member of the image-forming apparatus.
It is an object of the present invention, therefore, to provide a process cartridge for use in an image-forming apparatus with mechanism to restrain inherent longitudinal movement of the cartridge in the image-forming apparatus responsive to rotation of a photosensitive member carried in the process cartridge.